JP5431008B2 - Fuel cell stack - Google Patents

Description

  The present invention includes a fuel cell in which an electrolyte membrane / electrode structure provided with a pair of electrodes on both sides of an electrolyte membrane and a separator are stacked, and a plurality of the fuel cells are stacked. The present invention relates to a fuel cell stack provided with an end plate.

  For example, in a polymer electrolyte fuel cell, an electrolyte membrane / electrode structure (MEA) in which an anode side electrode and a cathode side electrode are disposed on both sides of an electrolyte membrane made of a polymer ion exchange membrane is sandwiched by separators. A unit cell is provided. This type of fuel cell is normally used as a fuel cell stack by stacking a predetermined number of unit cells.

  In this type of fuel cell stack, it is necessary to apply a desired tightening load in the stacking direction in order to obtain a desired power generation performance and to exert a sealing function.

  Therefore, for example, in the fuel cell disclosed in Patent Document 1, as shown in FIG. 9, pressure plates 3 a, 3 b are provided at both ends of a laminate in which a predetermined number of separators 1 and electrode units 2 are laminated. Is arranged. A holding member 4 having an L-shaped cross section is disposed at each corner of the pressure plate 3a, 3b, and the holding member 4 is fastened to the pressure plate 3a, 3b via a screw 5.

  That is, it is configured such that a clamping load in the stacking direction is applied to the separator 1 and the electrode unit 2 via the four holding members 4 fixed between the pressure plates 3a and 3b.

JP 2000-48850 A

  However, in Patent Document 1, each holding member 4 and the pressure plates 3a and 3b penetrate the holding member 4 through screw holes (not shown) formed in the side portions of the pressure plates 3a and 3b. Then, it is only fastened by the screw 5 to be screwed.

  Therefore, when a load is applied to the fuel cell from the outside, the outer shape of the stack is easily deformed. For this reason, there is a problem that the tightening load in the stacking direction cannot be maintained, and load loss occurs.

  Moreover, when an external force is applied to the fuel cell in the twisting direction, the torsional rigidity is low, and the fuel cell is likely to be twisted. As a result, particularly when used as an in-vehicle fuel cell, there is a problem that it is not possible to secure the holding rigidity against traveling vibration, external impact, and the like.

  The present invention solves this type of problem. A fuel cell stack that can reliably receive external loads and the like with a simple configuration and that can satisfactorily suppress deformation and loss of tightening loads. The purpose is to provide.

  The present invention includes a fuel cell in which an electrolyte membrane / electrode structure provided with a pair of electrodes on both sides of an electrolyte membrane and a separator are stacked, and a plurality of the fuel cells are stacked. The present invention relates to a fuel cell stack provided with an end plate.

The fuel cell stack includes a plurality of connecting members that are spanned between a pair of end plates in a direction parallel to the stacking direction and integrally hold the pair of end plates, and for connecting the connecting members to each other. And a coupling member.

  Moreover, it is preferable that a coupling member is comprised with the plate-shaped member fixed between connection members.

  Furthermore, it is preferable that the coupling member is composed of a brace member fixed between the coupling members.

  Furthermore, the fuel cell is provided with a plurality of fluid communication holes that communicate with each other in the stacking direction and respectively flow the reaction gas or the cooling medium, and the connection portion between the connection member and the side surface of the end plate is offset from the fluid communication hole. It is preferable to be provided at the position.

  According to the present invention, a pair of end plates are integrally held via a plurality of connecting members, and a desired tightening force can be reliably applied with a simple configuration. In addition, the connecting members are coupled to each other via a coupling member. For this reason, it is possible to reliably protect the fuel cell against an external force in a direction other than the direction in which the tightening load is supported, and to satisfactorily prevent the fuel cell from being deformed.

1 is a schematic perspective explanatory view of a fuel cell stack according to a first embodiment of the present invention. It is a principal part disassembled perspective explanatory drawing of the electric power generation cell which comprises the said fuel cell stack. It is a disassembled perspective explanatory drawing from one of the holding mechanism and fixing mechanism which comprise the said fuel cell stack. It is an exploded perspective view from the other of the holding mechanism and the fixing mechanism. FIG. 5 is a schematic perspective explanatory view of a fuel cell stack according to a second embodiment of the present invention. FIG. 5 is a schematic perspective view of another configuration of the fuel cell stack. It is a schematic perspective view of a fuel cell stack according to a third embodiment of the present invention. It is a disassembled perspective explanatory drawing of the holding mechanism and fixing mechanism which comprise the said fuel cell stack. 2 is a perspective view of a fuel cell according to Patent Document 1. FIG.

  As shown in FIG. 1, in the fuel cell stack 10 according to the first embodiment of the present invention, a plurality of fuel cells 12 are stacked in an arrow A direction (vertical direction) or an arrow B direction (horizontal direction), Terminal plates 14a and 14b, insulating plates 16a and 16b, and end plates 18a and 18b are disposed at both ends of the fuel cell 12 in the stacking direction.

  As shown in FIG. 2, the fuel cell 12 includes an electrolyte membrane / electrode structure 20 sandwiched between first and second separators 22 and 24. The first and second separators 22 and 24 are made of, for example, a metal separator such as a steel plate, a stainless steel plate, an aluminum plate, or a plated steel plate, or a carbon separator.

  One end edge of the fuel cell 12 in the direction of arrow B (the horizontal direction in FIG. 2) communicates with each other in the direction of arrow A, which is the stacking direction, and oxidant for supplying an oxidant gas, for example, an oxygen-containing gas An agent gas inlet communication hole 26a and a fuel gas inlet communication hole 28a for supplying a fuel gas, for example, a hydrogen-containing gas, are arranged in an arrow C direction (horizontal direction).

  The other end edge of the fuel cell 12 in the direction of arrow B communicates with each other in the direction of arrow A, the fuel gas outlet communication hole 28b for discharging the fuel gas, and the oxidant gas for discharging the oxidant gas. Outlet communication holes 26b are arranged in the direction of arrow C.

  A cooling medium inlet communication hole 30a for supplying a cooling medium and a cooling medium outlet communication hole 30b for discharging the cooling medium are provided at both ends of the fuel cell 12 in the arrow C direction.

  An oxidant gas passage 32 communicating with the oxidant gas inlet communication hole 26a and the oxidant gas outlet communication hole 26b is formed on a surface 22a of the first separator (cathode side separator) 22 facing the electrolyte membrane / electrode structure 20. Provided.

  A fuel gas flow path 34 communicating with the fuel gas inlet communication hole 28a and the fuel gas outlet communication hole 28b is provided on the surface 24a of the second separator (anode side separator) 24 facing the electrolyte membrane / electrode structure 20.

  A cooling medium that connects the cooling medium inlet communication hole 30a and the cooling medium outlet communication hole 30b between the surface 22b of the first separator 22 and the surface 24b of the second separator 24 that constitute the fuel cells 12 adjacent to each other. A flow path 36 is provided.

  The first seal member 38 is integrally or individually provided on the surfaces 22 a and 22 b of the first separator 22, and the second seal member 40 is integrally formed on the surfaces 24 a and 24 b of the second separator 24. Or it is provided separately.

  The first and second sealing members 38 and 40 are, for example, EPDM, NBR, fluorine rubber, silicon rubber, fluorosilicone rubber, butyl rubber, natural rubber, styrene rubber, chloroprene, or acrylic rubber or the like, cushioning material, Alternatively, a packing material is used.

  The electrolyte membrane / electrode structure 20 includes, for example, a solid polymer electrolyte membrane 42 in which a perfluorosulfonic acid thin film is impregnated with water, and a cathode side electrode 44 and an anode side electrode 46 that sandwich the solid polymer electrolyte membrane 42. With.

  The cathode side electrode 44 and the anode side electrode 46 are formed by uniformly applying a gas diffusion layer made of carbon paper or the like and porous carbon particles having a platinum alloy supported on the surface thereof to the surface of the gas diffusion layer. An electrode catalyst layer. The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 42.

  As shown in FIG. 1, for example, a plurality of connecting members 50 are bridged between end plates 18a, 18b made of aluminum. The connecting member 50 has, for example, a long plate shape made of aluminum, and two connecting members 50 are arranged on the long side of the fuel cell stack 10 and one on the short side of the fuel cell stack 10. Is done.

  The arrangement position of the connecting member 50 is set at a position (offset position) separated from the cooling medium inlet communication hole 30a and the cooling medium outlet communication hole 30b on the long side, whereas the oxidant gas inlet is set on the short side. They are set between the communication hole 26a and the fuel gas inlet communication hole 28a and between the oxidant gas outlet communication hole 26b and the fuel gas outlet communication hole 28b (offset position).

  The fuel cell stack 10 is provided on the side surfaces 51a and 51b of the end plates 18a and 18b and the connecting member 50, and a holding mechanism 52 for applying tension in the tightening direction (arrow A direction), and the end plates 18a and 18b. The side surfaces 51a, 51b and the connecting member 50 are provided with a fixing mechanism 54 for fixing the side surfaces 51a, 51b to each other.

  As shown in FIGS. 3 and 4, two holding mechanisms 52 are formed in each of the first hole portion 56 a formed in the side surfaces 51 a and 51 b of the end plates 18 a and 18 b and the upper and lower end portions of the connecting member 50. And a pin member 58 that is integrally inserted into the first and second holes 56a and 56b. The pin member 58 is made of, for example, an iron-based material.

  Reinforcing rings 60a and 60b made of, for example, an iron-based material are press-fitted into the first and second holes 56a and 56b, and the pin member 58 is integrally inserted into the reinforcing rings 60a and 60b.

  The fixing mechanism 54 includes screw holes 62 provided on the side surfaces 51 a and 51 b of the end plates 18 a and 18 b on both sides of the first hole portion 56 a and screws 64 fastened to the screw holes 62.

  A pair of hole portions 66 are formed in the connecting member 50 corresponding to the screw holes 62. A pin cover 68 is disposed on the surface side of the connecting member 50, and screws 64 are inserted into a pair of holes 70 formed in the pin cover 68. The screws 64 pass through the holes 66. Then, the screw hole 62 is tightened.

  In the connecting member 50, seal grooves 72a and 72b are formed around both end openings of the second hole portion 56b, and O-rings 74 are attached to the seal grooves 72a and 72b, respectively. A thick portion 76 is formed on the back surface side of the connecting member 50, that is, on the side surfaces 51a and 51b side of the end plates 18a and 18b. The thick portion 76 contacts the side surfaces 51a and 51b of the end plates 18a and 18b. Touch.

  As shown in FIG. 1, the connecting members 50 are coupled to each other via coupling members 80a and 80b. The coupling members 80a and 80b are made of, for example, aluminum which is the same material as that of the connecting member 50, but can be made of various materials as long as they are materials that do not cause potential difference corrosion due to the connection.

  The coupling member 80 a constitutes a long plate-like member for coupling between two coupling members 50 arranged on the long side of the fuel cell stack 10, while the coupling member 80 b is composed of the fuel cell stack 10. A plate-like member that is bent in an L shape is formed to connect the connecting members 50 disposed on the short side and the long side.

  Each connecting member 50 is formed with a plurality of screw holes 82 in two rows along the direction of the arrow A, and at both ends of the coupling members 80a and 80b, holes 84 corresponding to the screw holes 82 are formed. Are formed two by two. The coupling members 80 a and 80 b are fixed to the connecting member 50 by screwing the screw 86 inserted into the hole 84 into the screw hole 82. The coupling members 80a and 80b may be integrally formed.

  The end plate 18a includes an oxidant gas inlet communication hole 26a, a fuel gas inlet communication hole 28a, a cooling medium inlet communication hole 30a, an oxidant gas outlet communication hole 26b, a fuel gas outlet communication hole 28b, and a cooling medium outlet communication hole 30b. A manifold (not shown) that communicates and extends to the outside is provided, while the end plate 18b is configured as a closed flat plate.

  The operation of the fuel cell stack 10 configured as described above will be described below.

  First, as shown in FIG. 2, an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas inlet communication hole 26a, and a fuel gas such as a hydrogen-containing gas is supplied to the fuel gas inlet communication hole 28a. Further, a cooling medium such as pure water, ethylene glycol, or oil is supplied to the cooling medium inlet communication hole 30a.

  Therefore, the oxidant gas is introduced into the oxidant gas flow path 32 of the first separator 22 from the oxidant gas inlet communication hole 26a. The oxidant gas is supplied to the cathode side electrode 44 constituting the electrolyte membrane / electrode structure 20 while moving in the arrow B direction.

  On the other hand, the fuel gas is introduced into the fuel gas flow path 34 of the second separator 24 from the fuel gas inlet communication hole 28a. The fuel gas is supplied to the anode side electrode 46 constituting the electrolyte membrane / electrode structure 20 while moving in the arrow B direction.

  Therefore, in the electrolyte membrane / electrode structure 20, the oxidant gas supplied to the cathode side electrode 44 and the fuel gas supplied to the anode side electrode 46 are consumed by an electrochemical reaction in the electrode catalyst layer to generate power. Is done.

  Next, the oxidant gas consumed by being supplied to the cathode side electrode 44 is discharged in the direction of arrow A along the oxidant gas outlet communication hole 26b. On the other hand, the fuel gas consumed by being supplied to the anode electrode 46 is discharged in the direction of arrow A along the fuel gas outlet communication hole 28b.

  The cooling medium supplied to the cooling medium inlet communication hole 30a is introduced into the cooling medium flow path 36 between the first and second separators 22 and 24 and then flows in the direction of arrow C. After cooling the electrolyte membrane / electrode structure 20, the cooling medium is discharged from the cooling medium outlet communication hole 30b.

  In this case, in the first embodiment, in the fuel cell stack 10, a plurality of connecting members 50 are bridged between a pair of end plates 18a and 18b, and the end plates 18a and 18b are integrally held. Therefore, tension is applied to the connecting member 50 and the end plates 18a and 18b in the tightening direction, and the fastening force between the connecting member 50 and the end plates 18a and 18b is maintained. Therefore, it is possible to reliably apply a desired tightening force with a simple configuration.

  In addition, the connecting members 50 are coupled to each other via coupling members 80a and 80b. Accordingly, it is possible to reliably protect the fuel cell 12 against external force (such as falling or twisting) in a direction other than the direction in which the tightening load is supported, and to prevent the fuel cell 12 from being deformed. An effect is obtained.

  FIG. 5 is a schematic perspective view of a fuel cell stack 90 according to the second embodiment of the present invention.

  The same components as those of the fuel cell stack 10 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. Similarly, in the third embodiment described below, detailed description thereof is omitted.

  The fuel cell stack 90 includes a coupling member 92 for coupling the coupling members 50 to each other. The coupling member 92 has a brace structure, and is provided with a pair of upper and lower flat plate portions 92a and a plate-like bracing portion 92b that is within tolerance.

  Holes 94 are formed at the four corners of the coupling member 92, while screw holes 96 corresponding to the holes 94 are formed in the connecting member 50, which is disposed two each on the long side of the fuel cell stack 90. It is formed. When the screw 98 inserted into the hole 94 of the coupling member 92 is screwed into the screw hole 96, the coupling member 92 is fixed to the pair of coupling members 50.

  In the second embodiment configured as above, the pair of connecting members 50 are connected to each other by the connecting member 92 having a brace structure. Therefore, the same effects as those of the first embodiment can be obtained, such as the fuel cell 12 can be reliably protected against an external force (such as falling or twisting) in a direction other than the supporting direction of the tightening load.

  In the second embodiment, only the coupling member 92 is used. However, as shown in FIG. 6, for example, the coupling member 92 and a plurality of coupling members 80b can be used in combination. In addition, the connecting member 92 uses the two plate-like bracing portions 92b. However, the connecting member 92 may be one, and may employ a truss structure or the like in addition to the brace structure.

  FIG. 7 is a schematic perspective explanatory view of a fuel cell stack 100 according to the third embodiment of the present invention.

  The fuel cell stack 100 is provided on a connecting member 102 that spans between a pair of end plates 18a and 18b, side surfaces 51a and 51b of the end plates 18a and 18b, and the connecting member 102, and tensions each other in the tightening direction. A holding mechanism 104 for applying, a fixing mechanism 106 for fixing the side surfaces 51a, 51b of the end plates 18a, 18b and the connecting member 102, and a connecting member 80a for connecting the connecting members 102 to each other. 80b (and / or the coupling member 92).

  Similar to the connecting member 50, two connecting members 102 are arranged on the long side and one on the short side, respectively, and the oxidant gas inlet communication hole 26a and the fuel gas inlet communication hole 28a, respectively. The cooling medium inlet communication hole 30a, the oxidant gas outlet communication hole 26b, the fuel gas outlet communication hole 28b, and the cooling medium outlet communication hole 30b are provided at positions offset from each other.

  As shown in FIG. 8, the holding mechanism 104 is provided at both ends of the projections 108 provided on the side surfaces 51 a and 51 b of the end plates 18 a and 18 b and the connection member 102, and protrudes outward in the width direction of the connection member 102. And a protrusion 110 that engages with the protrusion 108.

  The protruding portion 108 is provided with a locking portion 108a that protrudes outward from the side surfaces 51a and 51b of the end plates 18a and 18b over a predetermined length and bulges at both ends. The protrusion 110 is disposed outward in the stacking direction across the protrusion 108, and a spacer member 112 for adjusting the dimension in the stacking direction is provided between the protrusion 108 and the protrusion 110. Intervened.

  The protrusion 110 is provided with a hook 114 that contacts the protrusion 108 by forming a step shape protruding toward the side surfaces 51a and 51b of the end plates 18a and 18b.

  The fixing mechanism 106 includes a screw hole 116 formed in the side surfaces 51a and 51b of the end plates 18a and 18b, a hole 118 formed in the protruding portion 110 of the connecting member 102, and the screw 118 inserted into the hole 118. And a screw 120 screwed into the hole 116. The protrusion 110 is provided with a recess 122 for arranging the screw 120.

  In the third embodiment configured as described above, the protrusions 110 provided at both ends in the longitudinal direction of the connecting member 102 are attached across the protrusions 108 provided on the end plates 18a and 18b. Yes. Therefore, the protrusion 108 and the protrusion 110 are pressure-bonded to each other, and tension is applied to the fuel cell stack 100 in the tightening direction. Furthermore, in the third embodiment, the connecting members 102 are integrally coupled via the coupling members 80a and 80b (and / or the coupling member 92), and are the same as in the first and second embodiments described above. The effect is obtained.

DESCRIPTION OF SYMBOLS 10, 90, 100 ... Fuel cell stack 12 ... Fuel cell 18a, 18b ... End plate 20 ... Electrolyte membrane and electrode structure 22, 24 ... Separator 26a ... Oxidant gas inlet communication hole 26b ... Oxidant gas outlet communication hole 28a ... Fuel gas inlet communication hole 28b ... Fuel gas outlet communication hole 30a ... Cooling medium inlet communication hole 30b ... Cooling medium outlet communication hole 32 ... Oxidant gas flow path 34 ... Fuel gas flow path 36 ... Cooling medium flow path 42 ... Solid polymer Electrolyte membrane 44 ... Cathode side electrode 46 ... Anode side electrode 50, 102 ... Connecting member 52, 104 ... Holding mechanism 54, 106 ... Fixing mechanism 56a, 56b, 66, 70, 84, 94, 118 ... Hole 58 ... Pin member 60a, 60b ... Reinforcing rings 62, 82, 96, 116 ... Screw holes 64, 86, 98, 120 ... Screws 74 ... O-rings 80a, 80b, 92 ... Coupling member 108 ... Projection 110 ... Projection 122 ... Recess

Claims (4)

A fuel cell in which an electrolyte membrane / electrode structure provided with a pair of electrodes on both sides of the electrolyte membrane and a separator are stacked, and a plurality of the fuel cells are stacked, and end plates are provided at both ends in the stacking direction. A fuel cell stack,
A plurality of connecting members that are stretched between a pair of the end plates in a direction parallel to the stacking direction and integrally hold the pair of end plates;
A coupling member for coupling the coupling members to each other;
A fuel cell stack comprising:   2. The fuel cell stack according to claim 1, wherein the coupling member is configured by a plate-like member fixed between the connecting members.   3. The fuel cell stack according to claim 1, wherein the coupling member includes a brace member fixed between the connecting members. 4. The fuel cell stack according to any one of claims 1 to 3, wherein the fuel cell includes a plurality of fluid communication holes that communicate with each other in the stacking direction and flow a reaction gas or a cooling medium, respectively.
A fuel cell stack, wherein a connecting portion between the connecting member and a side surface of the end plate is provided at a position offset from the fluid communication hole.

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